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June 28, 2011
Question

Help with making watermark that appears when photocopied or scanned

  • June 28, 2011
  • 5 replies
  • 30370 views

I need to create a textured background on a coupon.  Hidden in this background is the word VOID.  The word void won’t be very noticeable when you’re looking at a original coupon.  But if it’s photo copied or scanned, the word will appear. I will need to print the coupon on a monochrome laser printer.  I believe this can be accomplished with illustrator.  Has anyone done this?  Please help.  Thanks

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    5 replies

    July 5, 2011

    Thanks everyone for your input.  I was messing around with this over the weekend and found the solution.  It was a LOT easier than I thought it would be.  In fact I came up with many different patterns that worked.  In short I created a background texture.  I then overlaid the background texture on the font and made it perpendicular to the back ground.  I also rasterized it about ¼ of the resolution.  If you look for the security word, you can see it.  But it’s difficult because the pattern kind of blurs your vision.  When copied, the copier interprets the angles differently and makes one more prominent than the other.  The important thing is to keep the opacity of the background texture and the font the same.  This lets your vision blur them together. 

    Now for the million dollar question. OK, so I did what I was asked.  I hid a word in a background texture that became more noticeable when copied.  Is this really a security feature?  In my opinion NO, if it can be printed on your home laser printer than someone else can reproduce it.  That’s not secure.

    Jacob Bugge
    Community Expert
    Community Expert
    July 5, 2011

    For my part you are welcome, LaserTest.

    Is this really a security feature?  In my opinion NO,

    I agree.

    Besides, the difference you do see between the original and the copy may still depend on the equipment used; you would have to try it on a wide range of different equipment to be sure that it is consistent.

    June 29, 2011

    First I would like to thank everyone for your replies.  I also want to emphasize that I’m in total agreement that a true, quality, security watermark can only be achieved by use of specialty inks, varnishes, and more.  Personally I view this as a very basic attempt at creating a security watermark.  Unfortunately for me my boss is hell bent on this. 

    Good news though, and you all might find this interesting.  I just received two close-up images of this poor man’s security watermark.  The Master is the image that was printed on the monochrome laser printer and the Copy is the image that was produced by the copier after being photocopied. As you can see the copied image is not as crisp.  Hence the watermark is more apparent. The lower curved area is a piece of the font.  The rest is the textured background.  The font is filled with a 45 degree line pattern.  The background appears to be a halftone with a evenly spaced dot. 

    So I guess I should revamp my question to ask;

    1 How could I create a fill pattern for a font like this?

    2 How would I create a similar background pattern?

    Thanks in advance for your help.

    June 29, 2011

    WOW… Thanks for the quick response but don’t you think your throwing in the towel a little too easily.  I’m not saying that this is common and I will agree that newer scanners can produce a higher resolution which can defeat a low level watermark of this type.  I also agree that a truly anti-photocopy watermark will need to be produced by a printing company, not a desktop laser printer.  But to say Impossible I must disagree.  Somehow this person has done it.

    http://www.troygroup.com/industry/healthcare/products/printer/securerxprinter.aspx

    Mike_Gondek10189183
    Community Expert
    Community Expert
    June 29, 2011

    I believe that is built into the paper - probably some sort of chemical reaction that occurs when the paper is heated during the copy process. You could design the logo in Adobe CS, and have a printer add that into the paper.

    Do a search for security paper printing to find more places, but here is one

    http://www.protectedpaper.com/

    Mylenium
    Legend
    June 29, 2011

    What the others said - the whole idea won't work for a million reasons. Your own printing process alone can't deliver the goods here, as you are already introducing a raster that may make any hidden text more prominent - there is no way for even the best laser printer to print such soft greyscales without special toners/ inks. If this really is important, you will need to talk to a proper print shop who can do this with special UV/ infrared/ hi reflex inks, varnishes and ideally as a non-offset flexo process to retain contiguous features and edges....

    Mylenium

    Jacob Bugge
    Community Expert
    Community Expert
    June 28, 2011

    LaserTest,

    In order to be only become distinguishable when scanned/photocopied, the word has to have a shade that becomes darker and sharper in that process.

    Unfortunately, newer scanners photocopiers have options like (best) photo with rather convincing reproduction, quite different from older ones, so I am afraid it is impossible/very difficult.

    When you say monochrome, I presume you mean black (greyscale (or grayscale, especially over there)) only. If you could use another dark colour, especially one difficult to reproduce accurately, that might be a solution.

    _scott__
    Legend
    June 28, 2011

    Simply put... you can't on a monochrome laser printer.

    Special inks are used to add privacy features. You can't load special inks in a laser printer.